Parameterization of IR cooling in a Middle Atmosphere Dynamics Model: 2. Non-LTE radiative transfer and the globally averaged temperature of the mesosphere and lower thermosphere

1984 ◽  
Vol 89 (D3) ◽  
pp. 4917 ◽  
Author(s):  
John P. Apruzese ◽  
Darrell F. Strobel ◽  
Mark R. Schoeberl
Keyword(s):  
Radiative Transfer ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Dynamics Model ◽  
Middle Atmosphere Dynamics ◽  
Mesosphere And Lower Thermosphere

scholarly journals Large-Scale Waves in the Mesosphere and Lower Thermosphere Observed by SABER

2005 ◽  
Vol 62 (12) ◽  
pp. 4384-4399 ◽  
Author(s):  
Rolando R. Garcia ◽  
Ruth Lieberman ◽  
James M. Russell ◽  
Martin G. Mlynczak
Keyword(s):  
Large Scale ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Normal Modes ◽  
Zonal Winds ◽  
Broadband Emission ◽  
Summer Hemisphere ◽  
Mean Structure ◽  
Mesosphere And Lower Thermosphere ◽  
The Tropics

Abstract Observations made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board NASA’s Thermosphere–Ionosphere–Mesosphere Energetics and Dynamics (TIMED) satellite have been processed using Salby’s fast Fourier synoptic mapping (FFSM) algorithm. The mapped data provide a first synoptic look at the mean structure and traveling waves of the mesosphere and lower thermosphere (MLT) since the launch of the TIMED satellite in December 2001. The results show the presence of various wave modes in the MLT, which reach largest amplitude above the mesopause and include Kelvin and Rossby–gravity waves, eastward-propagating diurnal oscillations (“non-sun-synchronous tides”), and a set of quasi-normal modes associated with the so-called 2-day wave. The latter exhibits marked seasonal variability, attaining large amplitudes during the solstices and all but disappearing at the equinoxes. SABER data also show a strong quasi-stationary Rossby wave signal throughout the middle atmosphere of the winter hemisphere; the signal extends into the Tropics and even into the summer hemisphere in the MLT, suggesting ducting by westerly background zonal winds. At certain times of the year, the 5-day Rossby normal mode and the 4-day wave associated with instability of the polar night jet are also prominent in SABER data.

scholarly journals Global change induced trends in ion composition of the troposphere to the lower thermosphere

2008 ◽  
Vol 26 (5) ◽  
pp. 1181-1187 ◽  
Author(s):  
G. Beig
Keyword(s):  
Middle Atmosphere ◽  
Anthropogenic Activities ◽  
Lower Thermosphere ◽  
Cluster Ions ◽  
Atmospheric Density ◽  
Mesosphere And Lower Thermosphere ◽  
Induced Changes ◽  
Positive Ion ◽  
Mlt Region

Abstract. In this paper a brief overview of the changes in atmospheric ion compositions driven by the human-induced changes in related neutral species, and temperature from the troposphere to lower thermosphere has been made. It is found that ionic compositions undergo significant variations. The variations calculated for the double-CO2 scenario are both long-term and permanent in nature. Major neutrals which take part in the lower and middle atmospheric ion chemical schemes and undergo significant changes due to anthropogenic activities are: O, O2, H2O, NO, acetonitrile, pyridinated compounds, acetone and aerosol. The concentration of positive ion/electron density does not change appreciably in the middle atmosphere but indicates a marginal decrease above about 75 km until about 85 km, above which the magnitude of negative trend decreases and becomes negligible at 93 km. Acetonitrile cluster ions in the upper stratosphere are likely to increase, whereas NO+ and NO+(H2O) in the mesosphere and lower thermosphere (MLT) region are expected to decrease for the double CO2 scenario. It is also found that the atmospheric density of pyridinated cluster ions is fast rising in the troposphere.

scholarly journals A comparison of Rayleigh and sodium lidar temperature climatologies

2007 ◽  
Vol 25 (1) ◽  
pp. 27-35 ◽  
Author(s):  
P. S. Argall ◽  
R. J. Sica
Keyword(s):  
United States ◽  
Unique Feature ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Western United States ◽  
Lidar Measurements ◽  
Climatological Model ◽  
Significant Disagreement ◽  
Mesosphere And Lower Thermosphere ◽  
Rayleigh Lidar

Abstract. Temperature measurements from the PCL Rayleigh lidar located near London, Canada, taken during the 11 year period from 1994 to 2004 are used to form a temperature climatology of the middle atmosphere. A unique feature of the PCL temperature climatology is that it extends from 35 to 95 km allowing comparison with other Rayleigh lidar climatologies (which typically extend up to about 85 km), as well as with climatologies derived from sodium lidar measurements which extend from 83 to 108 km. The derived temperature climatology is compared to the CIRA-86 climatological model and to other lidar climatologies, both Rayleigh and sodium. The PCL climatology agrees well with the climatologies of other Rayleigh lidars from similar latitudes, and like these other climatologies shows significant differences from the CIRA-86 temperatures in the mesosphere and lower thermosphere. Significant disagreement is also found between the PCL climatology and sodium lidar climatologies measured in the central and western United States at similar latitudes, with the PCL climatology consistently 10 to 15 K cooler in the 85 to 90 km region.

scholarly journals The 16-day planetary wave in the mesosphere and lower thermosphere

1999 ◽  
Vol 17 (11) ◽  
pp. 1447-1456 ◽  
Author(s):  
N. J. Mitchell ◽  
H. R. Middleton ◽  
A. G. Beard ◽  
P. J. S. Williams ◽  
H. G. Muller
Keyword(s):  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Late Summer ◽  
Wave Activity ◽  
Motion Field ◽  
Mesopause Region ◽  
Waves And Tides ◽  
Mesosphere And Lower Thermosphere ◽  
Thermospheric Dynamics ◽  
The Uk

Abstract. A meteor radar located at Sheffield in the UK has been used to measure wind oscillations with periods in the range 10–28 days in the mesosphere/lower-thermosphere region at 53.5°N, 3.9°W from January 1990 to August 1994. The data reveal a motion field in which wave activity occurs over a range of frequencies and in episodes generally lasting for less than two months. A seasonal cycle is apparent in which the largest observed amplitudes are as high as 14 ms–1 and are observed from January to mid-April. A minimum in activity occurs in late June to early July. A second, smaller, maximum follows in late summer/autumn where amplitudes reach up to 7–10 ms–1. Considerable interannual variability is apparent but wave activity is observed in the summers of all the years examined, albeit at very small amplitudes near mid summer. This behaviour suggests that the equatorial winds in the mesopause region do not completely prevent inter-hemispheric ducting of the wave from the winter hemisphere, or that it is generated in situ.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides)

scholarly journals 3-D model for cosmic ray planetary ionisation in the middle atmosphere

2005 ◽  
Vol 23 (9) ◽  
pp. 3043-3046 ◽  
Author(s):  
P. I. Y. Velinov ◽  
L. Mateev ◽  
N. Kilifarska
Keyword(s):  
Cosmic Rays ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Spherical Shape ◽  
Cosmic Ray ◽  
Earth’S Atmosphere ◽  
Electron Production ◽  
Quantitative Understanding ◽  
Mesosphere And Lower Thermosphere ◽  
Earth's Atmosphere

Abstract. A 3-D planetary model of the cosmic ray electron production rate q(h) (cm-3 s-1) has been developed for the strato-mesosphere and lower thermosphere (altitude range 30-100 km) with a 10-km step. The spectrum of the primary cosmic rays is modelled by an analytical expression using input data from the CREME96 model. An isotropic penetration of the cosmic rays from the upper hemisphere is assumed in the model and a spherical shape of the Earth's atmosphere is taken into account. The longitudinal effect of ionisation from cosmic rays in the mesosphere and lower thermosphere is calculated. A graphical presentation of the computational results is given for 50 and 90 km at 0°, 40°, 50° and 70° N, S latitudes and all longitudes with a step of 30°. The results of this paper provide a basis for a quantitative understanding of the energetic processes of the middle atmosphere and mechanisms affecting the thermodynamical balance of the Earth's atmosphere.

scholarly journals On the Roles of Advection and Solar Heating in Seasonal Variation of the Migrating Diurnal Tide in the Stratosphere, Mesosphere, and Lower Thermosphere

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 440 ◽  
Author(s):  
Hongping Gu ◽  
Jian Du
Keyword(s):  
Seasonal Variation ◽  
Annual Variation ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Short Wave ◽  
Diurnal Tide ◽  
Physical Mechanisms ◽  
Wave Heating ◽  
Semiannual Variation ◽  
Mesosphere And Lower Thermosphere

The migrating diurnal tide (DW1) presents a unique latitudinal structure in the stratosphere, mesosphere, and lower thermosphere. In this paper, the physical mechanisms that govern its seasonal variation are examined in these three regions using the 31.5-year (1979–2010) output from the extended Canadian Middle Atmosphere Model (eCMAM30). DW1 annual variation in the stratosphere is mainly controlled by the short-wave heating in the high latitudes, but by both the short-wave and adiabatic heating in the low latitudes. In the mesosphere, linear and nonlinear advection play important roles in the semiannual variation of the tide whereas short-wave heating does not. In the lower thermosphere, the annual variation of DW1 is mainly governed by the short-wave heating and linear advection. This study illustrates the complexity of the main physical mechanisms modulating the seasonal variations of DW1 in different regions of the atmosphere.

scholarly journals Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010

2012 ◽  
Vol 30 (11) ◽  
pp. 1611-1621 ◽  
Author(s):  
J. Hedin ◽  
M. Rapp ◽  
M. Khaplanov ◽  
J. Stegman ◽  
G. Witt
Keyword(s):  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Meteor Shower ◽  
The Other ◽  
Sounding Rocket ◽  
Northern Norway ◽  
Smoke Particles ◽  
Meteoric Smoke ◽  
Mesosphere And Lower Thermosphere ◽  
Main Instrument

Abstract. In December 2010 the last campaign of the German-Norwegian sounding rocket project ECOMA (Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was conducted from Andøya Rocket Range in northern Norway (69° N, 16° E) in connection with the Geminid meteor shower. The main instrument on board the rocket payloads was the ECOMA detector for studying meteoric smoke particles (MSPs) by active photoionization and subsequent detection of the produced charges (particles and photoelectrons). In addition to photoionizing MSPs, the energy of the emitted photons from the ECOMA flash-lamp is high enough to also photoionize nitric oxide (NO). Thus, around the peak of the NO layer, at and above the main MSP layer, photoelectrons produced by the photoionization of NO are expected to contribute to, or even dominate above the main MSP-layer, the total measured photoelectron current. Among the other instruments on board was a set of two photometers to study the O2 (b1Σg+−X3Σg

scholarly journals Cooling of the mesosphere and lower thermosphere due to doubling of CO2

1998 ◽  
Vol 16 (11) ◽  
pp. 1501-1512 ◽  
Author(s):  
R. A. Akmaev ◽  
V. I. Fomichev
Keyword(s):  
Middle Atmosphere ◽  
Thermal Structure ◽  
Lower Thermosphere ◽  
Thermal Response ◽  
Co2 Concentration ◽  
Lower Atmosphere ◽  
Heating Rates ◽  
Density Reduction ◽  
Mesosphere And Lower Thermosphere ◽  
Thermospheric Dynamics

Abstract. A new parameterization of infrared radiative transfer in the 15-μm CO2 band has been incorporated into the Spectral mesosphere/lower thermosphere model (SMLTM). The parameterization is applicable to calculations of heating rates above approximately 15 km for arbitrary vertical profiles of the CO2 concentration corresponding to the surface mixing ratio in the range 150–720 ppm. The sensitivity of the mesosphere and lower thermosphere (MLT) to doubling of CO2 has been studied. The thermal response in the MLT is mostly negative (cooling) and much stronger than in the lower atmosphere. An average cooling at the stratopause is about 14 K. It gradually decreases to approximately 8 K in the upper mesosphere and again increases to about 40–50 K in the thermosphere. The cooling and associated thermal shrinking result in a substantial density reduction in the MLT that reaches 40–45% in the thermosphere. Various radiative, chemical, and dynamical feedbacks potentially important for the thermal response in the MLT are discussed. It is noted that the results of simulations are strikingly similar to observations of long-term trends in the MLT. This suggests that during the last 3–4 decades the thermal structure in the real upper atmosphere has undergone substantial changes driven by forcing comparable with that due to doubling of CO2.Key words. Meteorology and atmospheric dynamics (Climatology · Middle atmosphere dynamics · Thermospheric dynamics)

Sign in / Sign up

Export Citation Format

Share Document